Ray Rice sprained his knee in the fourth quarter of the Ravens' 24-17 win over Cleveland and didn't return.
Rice, the Ravens' leading rusher, doesn't have ligament damage, according to coach John Harbaugh. His status is unknown for Sunday's game at Pittsburgh.
"Right now, everything is standard," Rice said. "I'll take some tests on Monday, but everything looks positive right now."
Harbaugh was more vague.
"We don't know [the extent] for sure," Harbaugh said after the game.